Analysis of postnatal distribution of cortical interneurons. (A-H) Gad67 in situ hybridization analysis is shown on coronal hemi-sections through the forebrains of postnatal day (P)8 (A, E) and adult animals (C, G); in (B, F, D, H) sections of the cortices of the P8 and P45 brains, respectively, are shown in higher magnification. The regions shown in greater detail in the close-ups are outlined in the hemisections. Gad67+ interneurons can be seen throughout the entire width of the mutant cortex without exclusion from superficial layers both at P8 and in the adult (red arrowheads). The distribution of interneurons in the adult cortex was quantified by counting the cells in a 1 mm segment from lateral and medial cortex, respectively. (I) Schematic of a forebrain hemi-section illustrates the positions (framed by red bars) of the cortical segments that were counted. (J) Numbers of Gad67+ cells counted for WT and mutant medial (med) and lateral (lat) positions. Error bars indicate standard error. No significant differences in interneuron distribution were observed for the positions analyzed. All scale bars represent 250 μm. Cx, cerebral cortex; Fi, fimbria; HC, hippocampus; MZ, marginal zone; Pa, pallidum; St, striatum; Th, thalamus.